The overall objective of this research proposal is to investigate and understand the interactive effects of dietary calcium and NAC1 on vascular smooth muscle contractility by determining selected parameters. Two strains of rats (1) NaC1-sensitive Spontaneously Hypertensive Rat (SHR-S) (2) control Wistar Kyoto Rat (WKY) will be used in these investigations. Groups of six animals (both SHR-S and WKY) will be randomly placed for 12 weeks on four Calcium and Sodium altered diets: (a) 0.75% Na - 0.2% Ca: Low salt-low calcium (b) 0.75% Na - 2.0% Ca: Low salt- high calcium (c) 8% Na - 0.2% Ca: High salt-low calcium (d) 8% Na - 2.0% Ca: High salt-high calcium. The parameters to be studied are: membrane calcium dynamics (calcium efflux and influx) measured by cellular 45/Ca/2+ uptake and release, cytosolic free calcium concentration by fura-2 fluorescence technique, qualitative and quantitative characterization of calcium-binding proteins by electrophoresis, Western Blotting and autoradiographic methods, and contractile sensitivity studies. Systolic blood pressure will be measured monthly and at end of supplementation period by tail-cuff method and will be analyzed if the biochemical parameters determined are correlated with measured blood pressure by using appropriate statistical tests. Students will be benefitted by learning the above stated biomedical techniques in addition to having a better understanding of cellular mechanisms involved in blood pressure regulation and salt-sensitivity.